Why has world trade grown faster than world output?

By Mark Dean of the Bank’s International Economic Analysis Division and Maria Sebastia-Barriel of the Bank’s Structural Economic Analysis Division. Between 1980 and 2002, world trade has more than tripled while world output has ‘only’ doubled. The rise in trade relative to output is common across countries and regions, although the relative growth in trade and output varies greatly. This article attempts to explain why the ratio of world trade to output has increased over recent decades. It provides a brief review of the key determinants of trade growth and identifies proxies that will enable us to quantify the relative importance of the different channels. We estimate this across a panel of ten developed countries. This will allow us to understand better the path of world trade and thus the demand for UK exports. Furthermore this approach will help us to distinguish between long-run trends in trade growth and cyclical movements around it.

Introduction
In the past few decades there has been an increasing integration of the world economy through the increase of international trade. The volume of world trade(1) has increased significantly relative to world output between 1980 and 2002 (see Chart 1). Some of this increase can be accounted for by the fact that traded goods have become cheaper over time relative to those goods that are not traded. However, even in nominal terms the trade to GDP ratio has increased over this period. This means other factors may also be contributing to the phenomenon. Chart 1 World imports as a ratio of world GDP: nominal and real
Per cent 30 28 Real trade to GDP ratio 26 24 22 Nominal trade to GDP ratio 20 18 16 14 12 10 0

The upward trend in the trade to output ratio is evident since the end of the Second World War, and seems to have accelerated in the past 20 years. Prior to